Semiconductor device having metal thin film resistance element

ABSTRACT

A semiconductor device, includes a lower layer side insulation film; a wiring pattern formed on the lower layer side insulation film; a base insulation film formed on the lower layer side insulation film and the wiring pattern; and a plurality of metal thin film resistance elements formed on the base insulation film; wherein a connection hole is formed in the base insulation film on the wiring pattern; the wiring pattern and the metal thin film resistance element are electrically connected in the connection hole; the metal thin film resistance element has a belt shape part arranged separately from the connection hole and a connection part continuously formed with the belt shape part and connected to the wiring pattern in the connection hole; and the connection parts of at least two of the metal thin film resistance element are formed in the single connection hole with a gap in between said connection parts.

TECHNICAL FIELD

The present invention generally relates to semiconductor devices, andmore particularly to, a semiconductor device having a structure where alower layer side insulation film, a wiring pattern formed on the lowerlayer side insulation film, a base insulation film formed on the lowerlayer side insulation film and the wiring pattern, and plural metal thinfilm resistance elements formed on the base insulation film areprovided; a connection hole is formed in the base insulation film on thewiring pattern; and the wiring pattern and the metal thin filmresistance element are electrically connected in the connection hole.

BACKGROUND ART

In analog integrated circuits, resistance elements are frequently usedas important elements. Recently, a resistance element formed by a metalthin film (hereinafter “metal thin film resistance element”) in theresistance elements has attracted attention because the metal thin filmresistance element has a low TCR (temperature coefficient of resistance)of a resistance value. For example, chrome silicon (CRSI), nickel chrome(NICR), tantalum nitride (TAN), chrome silicide (CRSI₂), chrome silicidenitride (CRSIN), chrome silicon oxide (CRSI0), or the like is used as amaterial of the metal thin film resistance element.

In a semiconductor device having the metal thin film resistance element,in order to meet the demand of high integration, the metal thin filmresistance element may be frequently formed by a thin film having athickness equal to or less than 100 nm (1000 Å) so that a high sheetresistance is obtained.

In the related art, as a method for making electric connection of such ametal thin film resistance element, a method whereby a wiring pattern isformed on a lower layer side insulation film; a base insulation film isformed on the wiring pattern; a connection hole is formed in the baseinsulation film on the wiring patter; and the metal thin film resistanceelement is formed in the connection hole and on the base insulationfilm, has been used. See, for example, Japanese Laid-Open PatentApplication Publication No. 2002-124639.

A related art semiconductor device is discussed with reference to FIG. 1and FIG. 2. Here, FIG. 1 is a view showing the related art semiconductordevice, more specifically, FIG. 1(A) is a plan view of the related artsemiconductor device; FIG. 1(B) is a cross-sectional view taken along aline A-A of FIG. 1(A); and FIG. 1(C) is a cross-sectional view takenalong a line B-B of FIG. 1(A). FIG. 2 is an equivalent circuit of FIG.1(A).

Referring to FIG. 1 and FIG. 2, an interlayer insulation layer 5 isformed on an element isolation oxide film 3 formed on a siliconsubstrate 1. A metal wiring pattern 7 is formed on the interlayerinsulation layer 5. A base insulation film 9 is formed on an entiresurface of the interlayer insulation layer 5 including the metal wiringpattern 7.

A connection hole 45 is formed in the base insulation film 9 on themetal wiring pattern 7. A metal thin film resistance element 47 isformed on the base insulation film 9 including a forming area of theconnection hole 45.

A passivation film 15 is formed on the base insulation film 9 includinga forming area of the metal thin film resistance element 47 as a finalprotection film.

As shown in FIG. 1(B), a lower surface of the metal thin film resistance47 is electrically connected to the metal wiring pattern 7 in theconnection hole 45.

In addition, as shown in FIG. 1(A), plural metal thin film resistanceelements 47 are connected in series via the metal wiring patterns 7.

The metal thin film resistance elements 47 form a unit resistance. Thisunit resistance is prepared in various connection ways such as a blockof a series connection or a parallel connection of one metal thin filmresistance element, two metal thin film resistance elements, four metalthin film resistance elements, eight metal thin film resistanceelements, sixteen metal thin film resistance elements, thirty two metalthin film resistance elements, sixty four metal thin film resistanceelement and so on. A single or plural of these blocks are connected sothat a splitting resistance circuit or the like necessary for thecircuit is formed.

In the examples shown in FIG. 1 and FIG. 2, the metal thin filmresistance elements 47 of a single resistance R1, two resistances R2,and four resistances R3 are connected in series and the resistances R1,R2, and R3 are connected in series. When a voltage is applied betweenelectrodes A through D, voltages corresponding to a resistance ratio ofelectrodes B and C are output.

According to a connection method shown in FIG. 1, a substantialresistance value including resistance of an electrode per se, contactresistance of the electrode and the metal thin film resistance element,or the like substantially follows the number of the metal thin filmresistance elements. Therefore, it is possible to easily design andavoid unevenness of resistance values.

Meanwhile, the analog integrated circuit requires a lay-out using ametal thin film resistance element having width as narrow as possible sothat a large number of the metal thin film resistances are arranged.Therefore, the metal thin film resistance element is formed in an areaclose to the minimum resistance element pattern width that can be formedby a semiconductor process for manufacturing the analog integratedcircuit.

However, in a case where a hole for connecting or an electrode is formedby the metal thin film resistance element whose lay-out is made in thevicinity of the minimum width, if a sufficient space of overlappingbetween the connection hole and the metal thin film resistance elementis necessary, the connection hole may not be received in the width of asingle metal thin film resistance element due to the size of theconnection hole formed by a minimum size of the same process rule.

There are generally two methods as discussed below to correspond to thiscase.

(1) Only the connection hole forming part of the metal thin filmresistance element is made wide.

(2) As shown in FIG. 3, the structure where a single metal thin filmresistance element 47 is connected as the unit resistance is notapplied, but a meandering metal thin film resistance element is formedby connecting two belt shape parts 47 a with a turning part 47 b, and aconnection hole 45 a and the metal wiring pattern 7 are arranged underthe turning part 47 b. Here, FIG. 3 is a plan view showing anotherrelated art semiconductor device.

In the case of the above-mentioned (1), since the metal thin filmresistance element of the connection hole part is wide, the area of thelay-out of the metal thin film resistance element is increased.

On the other hand, in the case of the above-mentioned (2), since theconnection hole 45 a is arranged under the turning part 47 b connectedto two belt shape parts 47 a, it is possible to make the connection hole45 a larger than the width of the belt shape part 47 a withoutincreasing the lay-out area.

In addition, since the connection hole 45 a and the metal wiring pattern7 are provided at both ends of a single belt shape part 47 a, theresistance values corresponding to the number of the belt shape parts 47a may be easily obtained.

However, in the lay-out of the above-mentioned (2), as shown by an arrowin FIG. 3, at the turning part 47 b of the metal thin film resistanceelement, the electrical current flows not to the connection hole 45 a orthe metal wiring pattern 7 but via an overlapping space part. Forexample, at extended parts such as the electrodes A through D, anelectric current flows via the connection hole and the electrode partand therefore a designated resistance value or resistance ratio is notobtained. Such a problem may occur more frequently as the number of thebelt shape part 47 a and the turning part 47 b connected in series isincreased.

SUMMARY

In an aspect of this disclosure, there is provided a semiconductordevice having an integrated circuit including a metal thin filmresistance element wherein a resistance value that is the same as adesign value can be obtained without increasing a lay-out area of themetal thin film resistance element.

In another aspect of this disclosure, there is provided a semiconductordevice that includes: a lower layer side insulation film; a wiringpattern formed on the lower layer side insulation film; a baseinsulation film formed on the lower layer side insulation film and thewiring pattern; and a plurality of metal thin film resistance elementsformed on the base insulation film; wherein a connection hole is formedin the base insulation film on the wiring pattern; the wiring patternand the metal thin film resistance element are electrically connected inthe connection hole; the metal thin film resistance element has a beltshape part arranged separately from the connection hole and a connectionpart continuously formed with the belt shape part and connected to thewiring pattern in the connection hole; and the connection parts of atleast two of the metal thin film resistance element are formed in thesingle connection hole with a gap in between said connection parts.

According to the above-mentioned semiconductor device, it is possible tomake the connection hole larger than the width of the belt shape partand therefore an area of the lay-out is not increased.

As a result of this, it is possible to make lay-out of the metal thinfilm resistance elements without limiting the size of the connectionhole. Hence, it is possible to make the area of the lay-out small and achip size small.

In addition, since plural connection parts formed in a single connectionhole are formed with a gap in between, electrical current flows via thewiring pattern if plural metal thin film resistance elements areconnected in series. Therefore, in the embodiment of the presentinvention, unlike the related art shown in FIG. 3, the electricalcurrent does not flow via the turning part 47 b so that a designatedresistance value is obtained and an analog circuit having high precisioncan be designed.

In the semiconductor device, the connection part may be wider than thebelt shape part.

According to the above-mentioned semiconductor device, it is possible tomake a space of overlapping of the connection part and the connectionhole large.

In the semiconductor device, the gap between the connection partsneighboring in the connection hole may be narrower than a gap betweenneighboring belt shape parts.

According to the above-mentioned semiconductor device, as compared witha case where the gap between the neighboring connection parts is thesame as the gap between the neighboring belt-shape parts, it is possibleto make a contact area of the metal thin film and the wiring patternlarger so that the contact resistance can be reduced.

The semiconductor device may further include a first connection partmade of a metal thin film whose material is the same as the material ofthe metal thin film resistance element, which first connection part isconfigured to connect the connection parts neighboring in the connectionhole.

According to the above-mentioned semiconductor device, it is possible tomake a contact area of the metal thin film and the wiring pattern largerso that the contact resistance can be reduced.

The semiconductor device may further include a second connection partmade of a metal thin film whose material is the same as the material ofthe metal thin film resistance element, which second connection part isconfigured to connect the connection parts neighboring outside theconnection hole at a side opposite to the belt shape part from theconnection hole.

According to the above-mentioned semiconductor device, it is possible toreduce influence where the end part of the connection part is curved dueto properties of photo engraving so that the width of the overlappingpart can be made large.

In another aspect of this disclosure, a semiconductor device includes asplitting resistance circuit configured to obtain high precision of avoltage output by splitting the voltage output with a plurality ofresistance elements and adjusting the voltage output by cutting a fuseelement; wherein the resistance element is formed by the metal thin filmresistance element mentioned above.

According to the above-mentioned semiconductor device, it is possible tomake the resistance value of the resistance element stable by using themetal thin film resistance elements forming the semiconductor device ofthe embodiment of the present invention. Therefore, it is possible toimprove precision of output voltage of a splitting resistance circuit.

In another aspect of this disclosure, there is provided a semiconductordevice that includes: a first splitting resistance circuit configured tosplit an input voltage and supply a split voltage; a standard voltagegeneration circuit configured to supply a standard voltage; and avoltage detection circuit having a comparison circuit configured tocompare the split voltage from the first splitting resistance circuitand the standard voltage from the standard voltage generation circuit;wherein the first splitting resistance circuit has the splittingresistance circuit mentioned above.

According to the above-mentioned semiconductor device, it is possible toimprove precision of the output voltage by the splitting resistancecircuit where the present invention is applied. Therefore, it ispossible to improve the precision of voltage detection of the voltagedetection circuit.

In another aspect of this disclosure, there is provided a semiconductordevice that includes: an output driver configured to control output ofan input voltage; a first splitting resistance circuit configured tosplit an output voltage and supply a split voltage; a standard voltagegeneration circuit configured to supply a standard voltage; and aconstant voltage generation circuit having a comparison circuitconfigured to compare the split voltage from the first splittingresistance circuit and the standard voltage from the standard voltagegeneration circuit; wherein the first splitting resistance circuit hasthe splitting resistance circuit mentioned above.

According to the above-mentioned semiconductor device, it is possible toimprove the precision of the output voltage by the splitting theresistance circuit where the present invention is applied. Therefore, itis possible to make output voltage of the constant voltage generationcircuit stable.

The above-mentioned and other aspects, features, and advantages willbecome more apparent from the following detailed description when readin conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a view showing a related art semiconductor device, morespecifically, FIG. 1(A) is a plan view of the related art semiconductordevice; FIG. 1(B) is a cross-sectional view taken along a line A-A ofFIG. 1(A); and FIG. 1(C) is a cross-sectional view taken along a lineB-B of FIG. 1(A);

FIG. 2 is an equivalent circuit of FIG. 1(A), FIG. 3 and FIG. 4(A);

FIG. 3 is a plan view showing another related art semiconductor device;

FIG. 4 is a view showing a semiconductor device of an embodiment of thepresent invention, more specifically, FIG. 4(A) is a plan view showing apart of a forming area of a metal thin film resistance element; FIG.4(B) is a cross-sectional view taken along a line A-A of FIG. 4(A); andFIG. 4(C) is a cross-sectional view taken along a line B-B of FIG. 4(A);

FIG. 5 is a plan view showing the vicinity of a connection hole of otherembodiments of the present invention;

FIG. 6 is a plan view showing the vicinity of a connection hole of otherembodiment of the present invention;

FIG. 7 is a circuit diagram showing an example of a semiconductor devicehaving a constant voltage generation circuit that is an analog circuit;

FIG. 8 is a circuit diagram showing an example of a semiconductor devicehaving a voltage generation circuit that is an analog circuit;

FIG. 9 is a circuit diagram showing an example of a semiconductor devicehaving a splitting resistance circuit that is an analog circuit;

FIG. 10 is a lay-out view of an example of a lay-put of a fuse elementpart of the splitting resistance circuit; and

FIG. 11 is a graph showing an output voltage distribution after trimmingin plural samples of the constant voltage generation circuit where thepresent invention is applied, more specifically, FIG. 11(A) is a graphin a case of the present invention and FIG. 11(B) is a graph of acomparison example wherein the vertical axis shows frequency and thehorizontal axis shows an output voltage.

BEST MODE FOR CARRYING OUT THE INVENTION

A description of the present invention is now given, with reference toFIG. 4 through FIG. 11, including embodiments of the present invention.

FIG. 4 is a view showing a semiconductor device of an embodiment of thepresent invention. More specifically, FIG. 4(A) is a plan view showing apart of a forming area of a metal thin film resistance element; FIG.4(B) is a cross-sectional view taken along a line A-A of FIG. 4(A); andFIG. 4(C) is a cross-sectional view taken along a line B-B of FIG. 4(A).

In FIG. 4(A), illustrations of a base insulation film and a passivationfilm are omitted. In the embodiment discussed below, while a transistorelement, a capacitor element, or the like is formed on the samesubstrate, illustration of these elements is omitted in drawings.

An equivalent circuit of this embodiment is the same as the circuitshown in FIG. 2.

In this embodiment, an element isolation oxidization film 3 is formed ona silicon substrate 1. An interlayer insulation film (lower layer sideinsulation film) 5 is formed on the element isolation oxidization film 3formed on the silicon substrate 1.

The interlayer insulation film 5 is made of a BPSG (Borophospho SilicateGlass) film or a PSG (Phospho Silicate Glass) film. A metal wiringpattern 7 is formed on the interlayer insulation film 5. The metalwiring pattern is formed by, for example, an AlSiCu (Cu=0.5%, Si=1.0%)film.

A base insulation film 9 is formed on the interlayer insulation film 5including a forming area of the metal wiring pattern 7. The baseinsulation film 9 is formed by, for example, from a lower layer side, aplasma CVD (Chemical Vapor Deposition) oxidization film and a SOG (SpinOn Glass) layer. These layers are illustrated in a body in FIG. 4. Thethickness of the base insulation film 9 is, for example, approximately650 nm (6500 Å).

A connection hole 11 is formed in the base insulation film 9 so as tocorrespond to a connection part of a metal thin film resistance elementand the metal wiring pattern 7. The connection hole 11 has measurementof, for example, approximately 2.6×1.4 μm.

A CrSiN thin film resistance element (metal thin film resistanceelement) 13 is formed on the base insulation film 9 including a formingarea of the connection hole 11. The CrSiN thin film resistance element13 includes a band shape part 13 a and connection parts 13 b provided atboth ends of the band shape part 13 a.

The band shape part 13 a is arranged so as to be separated from theconnection hole 11. The connection part 13 b is formed from the end partof the band shape part 13 a into the connection hole 11. In theconnection hole 11, the connection part 13 b is electrically connectedto the metal wiring pattern 7. In a single connection hole 11, theconnection parts 13 b of two CrSiN thin film resistance resistances 13are formed with a gap in between.

The film thickness of the CrSiN thin film resistance element 13 is, forexample, approximately 8 nm (80 Å). The CrSiN thin film resistanceelement 13 is formed by a target of Si/Cr=60/40 wt % under a conditionof N₂ partial pressure=20%. The width of the CrSiN thin film resistanceelement 13 is, for example, approximately 1.2 μm. The gap betweenneighboring CrSiN thin film resistance elements 13 is, for example,approximately 1.0 μm.

A passivation film 15 as a final protection film is formed on the baseinsulation film 9 including a forming area of the CrSiN thin filmresistance element 13. The passivation film 15 is formed by, forexample, a silicon oxide film situated at a lower layer side and asilicon nitride layer situated at an upper layer side. These layers areillustrated in a body in FIG. 4.

Thus, in this embodiment, the CrSiN thin film resistance element 13includes the belt shape part 13 a arranged separately from theconnection hole 11 and the connection part 13 b continuously formed withthe belt shape part 13 a and connected to the metal wiring pattern 7. Inaddition, the connection parts 13 b of two CrSiN thin film resistanceelements 13 are formed with a gap in between in a single connection hole11.

Therefore, the connection hole 11 can be larger than the width of thebelt shape part 13 a and therefore the area of the lay-out is notincreased. Because of this, since the lay-out of the CrSiN thin filmresistance element 13 can be made without limiting the size of theconnection hole 11, it is possible to make the area of the lay-out smallso that the chip size can be made small.

In addition, since two connection parts 11 a formed in a singleconnection hole 11 are formed with a gap in between, an electricalcurrent flows via the wiring pattern 7 when plural metal thin filmresistance elements 13 are connected in series.

Accordingly, in this embodiment unlike the related art shown in FIG. 3,the electrical current does not flow via the turning part 47 b so that adesignated resistance value is obtained and an analog circuit havinghigh precision can be designed.

FIG. 5 is a plan view showing the vicinity of a connection hole of otherembodiments of the present invention;

In an example shown in FIG. 5(A), the width of the connection part 13 bis greater than the width of the belt shape part 13 a so that the gapbetween the connection parts 13 b neighboring in the connection hole 11is narrower than the gap between the belt shape parts 13 a neighboringthe connection hole 11.

According to the example shown in FIG. 5(A), as compared to a case wherethe gap between the connection parts 13 b neighboring in the connectionhole 11 is the same as the gap between the belt shape parts 13 aneighboring the connection hole 11, it is possible to make a contactarea of the connection part 13 b and the wiring pattern 7 larger so thatcontact resistance can be reduced.

In addition, since the width of the connection part 13 b is greater thanthe width of the belt shape part 13 a, it is possible to make anoverlapping space of the connection part 13 b and the connection hole11.

In an example shown in FIG. 5(B), a side in a longitudinal direction ofthe connection part 13 b and not overlapping the connection hole 11 isextended to the outside, namely in a direction opposite to theconnection hole 11 so that the connection part 13 b is wider than thebelt shape part 13 a.

According to the example shown in FIG. 5(B), it is possible to make theoverlapping space of the connection part 13 b and the connection hole 11large.

In an example shown in FIG. 5(C), a configuration of the connection part13 b is formed by combining the configuration of the connection part 13b in the example shown in FIG. 5(A) and the configuration of theconnection part 13 b in the example shown in FIG. 5(B).

According to the example shown in FIG. 5(C), it is, possible to realizea decrease of the contact resistance and an increase of the overlappingspace of the connection part 13 b and the connection hole 11.

In an example shown in FIG. 5(D), a first connection part 13 c and asecond connection part 13 d are provided. The first connection part 13 cconnects connection parts 13 b neighboring in the connection hole 11.The second connection part 13 d connects connection parts 13 bneighboring outside of the connection hole 11 at a side opposite to thebelt shape part 13 a from the connection hole 11.

The first connection part 13 c and the second connection part 13 d aremade of a metal thin film whose material is the same as that of theCrSiN thin film resistance element 13, namely CrSiN.

According to the example shown in FIG. 5(D), it is possible to make thecontact area of the metal thin film and the wiring pattern 7 large bythe first connection part 13 c so that contact resistance can bereduced.

In addition, it is possible to reduce influence where the end part ofthe connection part 13 b is curved due to properties of photo engravingby the second connection part 13 d so that width of the overlapping partcan be made large.

In an example shown in FIG. 5(E) as compared to the example shown inFIG. 5(D), the connection part 13 c is formed so as to retreat from thebelt shape part 13 a.

According to the example shown in FIG. 5(E), even if an overlappingshift is generated in a longitudinal direction of the belt shape part 13a, it is possible to prevent the belt shape parts 13 a from beingconnected by the connection part 13 c at a belt shape part 13 a side ofthe connection hole 11.

In an example shown in FIG. 5(F) as compared to the example shown inFIG. 5(D), the connection part 13 c is not formed.

According to the example shown in FIG. 5(F), it is possible to reduceinfluence where the end part of the connection part 13 b is curved dueto properties of photo engraving by the second connection part 13 d sothat width of the overlapping part can be made large.

In an example shown in FIG. 5(G) as compared to the example shown inFIG. 5(E), the second connection part 13 d is not formed.

According to the example shown in FIG. 5(G), it is possible to make thecontact area of the metal thin film and the wiring pattern 7 large bythe first connection part 13 c so that contact resistance can bereduced.

In the example shown in FIG. 5(G) as well as the example shown in FIG.5(D), the connection part 13 c may be formed to be the same size as thatof the connection hole 11 in a longitudinal direction of the belt shapepart 13 a. However, considering an overlapping space, it is preferablethat at least an end part at a side of the belt shape part 13 a beformed so as to retract from the connection part 13 c.

In addition, in the examples shown in FIG. 5(D), FIG. 5(E), FIG. 5(F)and FIG. 5(G) as well as the examples shown in FIG. 5(A), FIG. 5(B), andFIG. 5(C), line width of the connection part 13 b may be greater thanthe belt shape part 13 a so as to have the same effect as that of theexamples shown in FIG. 5(A), FIG. 5(B), and FIG. 5(C).

In the above-discussed embodiment, two connection parts 13 b are formedin a single connection hole 11. However, the present invention is notlimited to this. The number of the connection parts of the metal thinfilm resistance element formed in a single connection hole may be equalto or greater than three.

For example, as shown in FIG. 6, three connection parts 13 b may beformed in a single connection hole 11. Here, FIG. 6 is a plan viewshowing the vicinity of a connection hole of another embodiment of thepresent invention.

In a case where the number of the connection parts of the metal thinfilm resistance element formed in a single connection hole is equal toor greater than three, the linear width of the connection part 13 may bewide as shown in FIG. 5(A), FIG. 5(B) and FIG. 5(C); the connectionparts 13 c and 13 d may be provided as shown in FIG. 5(D), FIG. 5(E),FIG. 5(F) and FIG. 5(G); or they may be combined.

In the above-discussed embodiment, the passivation film 15 is formed onthe CrSiN thin film resistance element 13. However, the presentinvention is not limited to this. The insulation film formed on theCrSiN thin film resistance element 13 may be any insulation film such asan interlayer insulation film for forming a metal wiring pattern of asecond layer.

In the above-discussed embodiment, the present invention is applied tothe semiconductor device having a single layer of the metal wiringpattern. However, the present invention is not limited to this. Thepresent invention may be applied to a semiconductor device with amultilayer metal wiring structure having two or more layers of the metalwiring patterns. In this case, in order to obtain electrical connectionof the metal thin film resistance element, the metal wiring of a lowerlayer of the metal thin film resistance element may be a metal wiringpattern of any layer.

In the above-discussed embodiment, a metal material pattern 7 is used asa wiring pattern for making electrical connection of the CrSiN thin filmresistance element. However, the present invention is not limited tothis. For example, a wiring pattern made of other metal material or apolysilicon wiring pattern made of polysilicon may be used.

In the above-discussed embodiment, CrSiN is used as the material of themetal thin film resistance element. However, the present invention isnot limited to this. Other material such as NiCr, TaN, CrSi₂, CrSi, orCrSiO may be used as the material of the metal thin film resistanceelement.

The metal thin film resistance element forming the semiconductor deviceof the embodiment of the present invention can be applied to asemiconductor device having, for example, an analog circuit. In thefollowing description, an example of a semiconductor device having ananalog circuit including the metal thin film resistance element of theembodiment of the present invention is discussed.

FIG. 7 is a circuit diagram showing an example of a semiconductor devicehaving a constant voltage generation circuit that is an analog circuit.

Referring to FIG. 7, a constant voltage generation circuit 25 isprovided so as to stably supply electric power from a DC (directcurrent) power supply 21 to a load 23. The constant voltage generationcircuit 25 includes an input terminal (Vbat) 27 where the DC powersupply 21 is connected, a standard voltage generation circuit (Vref) 29,an operational amplifier (comparison circuit) 31, a P channel MOStransistor (hereinafter “PMOS”) 33 forming an output driver, splittingresistance elements R1 and R2, and an output terminal (Vout) 35.

In the operational amplifier 31 of the constant voltage generationcircuit 25, the following control is implemented. That is, the outputterminal is connected to a gate electrode of the PMOS 33; a standardvoltage Vref is applied from the standard voltage generation circuit 29to an inversing input terminal (−); and a voltage produced by dividingthe output voltage Vout with the resistance elements R1 and R2 isapplied to a non-inverting input terminal (+), so that the split voltageof the resistance elements R1 and R2 becomes equal to the standardvoltage Vref.

FIG. 8 is a circuit diagram showing an example of a semiconductor devicehaving a voltage generation circuit that is an analog circuit.

Referring to FIG. 8, in a voltage detection circuit 37, the numericalreference 31 denotes an operational amplifier. The standard voltagegeneration circuit 29 is connected to a inverting input terminal (−) sothat the standard voltage Vref is applied. A voltage of a terminal to bemeasured, which voltage is input from the input terminal (Vsens) isdivided by the splitting resistance elements R1 and R2 so that thedivided voltage is input to the non-inverting input terminal (+) of theoperational amplifier 31. The output of the operational amplifier 31 isoutput to the outside via the output terminal (Vout) 41.

In the voltage detection circuit 37, if the voltage at the terminal tobe measured is high so that the voltage divided by the splittingresistance elements R1 and R2 is higher than the standard voltage Vref,an H level of the output of the operational amplifier 31 is maintained.

If the voltage at the terminal to be measured is decreased so that thevoltage divided by the splitting resistance elements R1 and R2 is equalto or less than the standard voltage Vref, the output of the operationalamplifier 31 becomes an L level.

Generally, in the constant voltage generation circuit shown in FIG. 7and the voltage detection circuit shown in FIG. 5, the standard voltageVref from the standard voltage generation circuit is changed due tounevenness of a manufacturing process. Therefore, in order to respond tothis change, the resistance value of the splitting resistance elementsis adjusted by using a resistance element circuit (hereinafter“splitting resistance circuit”) whereby the resistance value can beadjusted by cutting a fuse element as a splitting resistance element orby using a splitting resistance circuit whereby the resistance value canbe adjusted by laser irradiation onto the resistance element.

FIG. 9 is a circuit diagram showing an example of a semiconductor devicehaving a splitting resistance circuit that is an analog circuit. FIG. 10is a plan view of an example of a lay-out of a fuse element part of thesplitting resistance circuit. The lay-out of the resistance element partis the same as that shown in FIG. 4(A).

As shown in FIG. 9, a resistance element Rbottom, “m+1 (“m” is apositive integer)” pieces of resistance elements RT, RT1, . . . , RTm,and a resistance element Rtop are connected in series. Corresponding tothe resistance elements, fuse elements RL0, RL1, . . . , RLm areconnected in parallel to the corresponding resistance elements RT, RT1,. . . , RTm.

FIG. 10 is a plan view of an example of a lay-out of a fuse element partof the splitting resistance circuit.

As shown in FIG. 10, the fuse elements RL0, RL1, . . . , RLm are formedby a polysilicon pattern having sheet resistance of, for example,approximately 20Ω through 40 Ω.

Values of the resistance elements RT, RT1, . . . , RTm are increased ina binary number manner from a side of the resistance element Rbottom. Inother words, the resistance value of the resistance element RTn is 2ntimes the unit value that is the resistance value of the resistanceelements RT0.

In FIG. 4 and FIG. 10, electrical connection between the electrodes A-A,electrodes B-B, electrodes C-C, and electrodes D-D are made by the metalwiring pattern.

Thus, in the splitting resistance circuit wherein precision of the ratiobetween the resistance element is critical, in order to improve formingprecision in the manufacturing process, unit resistance elements made ofa couple of the resistance elements and the fuse elements are connectedin series and arrange in a ladder structure.

In such a splitting resistance circuit, by cutting optional fuseelements RL0, RL1, . . . , RLm with a laser light, it is possible toobtain a desirable series resistance value.

As discussed above, with the metal thin film resistance element formingthe semiconductor device of the embodiment of the present invention, itis possible to make the resistance value of the resistance elementstable. Therefore, it is possible to improve the precision of the outputvoltage of the splitting resistance circuit shown in FIG. 9.

In a case where the splitting resistance circuit shown in FIG. 9 isapplied to the splitting resistance elements R1 and R2 of the constantvoltage generation circuit 25 shown in FIG. 1, for example, the end ofthe resistance element Rbottom is grounded and the end of the resistanceelement Rtop is connected to a drain of the PMOS 33.

In addition, a terminal NodeL between the resistance element Rbottom andRT0 or a terminal NodeM between the resistance element Rtop and RTm isconnected to a non-inverting input terminal of the operational amplifier31.

According to the splitting resistance circuit where the presentinvention is applied, it is possible to improve precision of the outputvoltage of the splitting resistance circuit. Therefore, it is possibleto make the output voltage of the constant voltage generation circuit 25stable.

In a case where the splitting resistance circuit shown in FIG. 9 isapplied to the splitting resistance elements R1 and R2 of the voltagedetection circuit 37 shown in FIG. 8, for example, the end of theresistance element Rbottom is grounded and the end of the resistanceelement Rtop is connected to the input terminal 61.

In addition, a terminal NodeL between the resistance element Rbottom andRT0 or a terminal NodeM between the resistance element Rtop and RTm isconnected to a non-inverting input terminal of the operational amplifier31.

According to the splitting resistance circuit where the presentinvention is applied, it is possible to improve precision of the outputvoltage of the splitting resistance circuit. Therefore, it is possibleto improve the precision of the voltage detection ability of the voltagedetection circuit 37.

FIG. 11 is a graph showing an output voltage distribution after trimmingin plural samples of the constant voltage generation circuit where anembodiment of the present invention is applied. More specifically, FIG.11(A) is a graph in a case of the present invention and FIG. 11(B) is agraph of a comparison example wherein the vertical axis shows frequencyand the horizontal axis shows an output voltage.

A metal thin film resistance element of a sample in the case of FIG.11(A) is formed under conditions of the example discussed with referenceto FIG. 4.

A metal thin film resistance body of a comparison example of FIG. 11(B)includes the turning part of the related art discussed with reference toFIG. 3. Other conditions are same as the conditions of the embodimentsdiscussed with reference to FIG. 4.

In the constant voltage generation circuit (A) where the presentinvention is applied, compared to the comparison example (B), standarddeviation a is improved so as to be approximately half of the standarddeviation of (B).

The present invention is not limited to these embodiments, butvariations and modifications may be made without departing from thescope of the present invention.

While the examples of the semiconductor device where the splittingresistance circuit having the metal thin film resistance element of thepresent invention is applied is discussed with reference to FIG. 4 andFIG. 7 through FIG. 10, the semiconductor device where the splittingresistance circuit is applied is not limited to the semiconductor devicehaving the constant voltage generation circuit or the semiconductordevice having the voltage detection circuit. The present invention maybe applied to any semiconductor device having the splitting resistancecircuit.

In addition, the semiconductor device where the metal thin filmresistance element of the present invention is applied is not limited tothe semiconductor device having the splitting resistance circuit. Thepresent invention may be applied to any semiconductor device having themetal thin film resistance element.

This patent application is based on Japanese Priority Patent ApplicationNo. 2005-299767 filed on Oct. 14, 2005, the entire contents of which arehereby incorporated by reference.

1. A semiconductor device, comprising: a lower layer side insulationfilm; a wiring pattern formed on the lower layer side insulation film; abase insulation film formed on the lower layer side insulation film andthe wiring pattern; and a plurality of metal thin film resistanceelements formed on the base insulation film; wherein a connection holeis formed in the base insulation film on the wiring pattern; the wiringpattern and the metal thin film resistance element are electricallyconnected in the connection hole; wherein each of the metal thin filmresistance elements comprises a belt shape part arranged separately fromthe connection hole and a connection part continuously formed with oneend of the belt shape part and connected to the wiring pattern in theconnection hole; and wherein for each of the connection parts of atleast two respectively elements of the plurality of metal thin filmresistance elements, a portion of the connection part is formed in theconnection hole, wherein a gap is between the connection partsneighboring in the connection hole, and wherein the connection partsbelong to respective separate metal thin film resistance elements. 2.The semiconductor device as claimed in claim 1, wherein the connectionpart is wider than the belt shape part.
 3. The semiconductor device asclaimed in claim 1, wherein the gap between the connection partsneighboring in the connection hole is narrower than another gap betweenneighboring belt shape parts.
 4. The semiconductor device as claimed inclaim 2, wherein the gap between the connection parts neighboring in theconnection hole is narrower than another gap between neighboring beltshape parts.
 5. The semiconductor device of claim 1, further comprising:a splitting resistance circuit including a plurality of fuse elementsconnected in parallel to the plurality of metal thin film resistanceelements, respectively, wherein the plurality of metal thin filmresistance elements splits a voltage output and the voltage output isadjusted by cutting one or more of the fuse elements.
 6. Thesemiconductor device of claim 2, further comprising: a splittingresistance circuit including a plurality of fuse elements connected inparallel to the plurality of metal thin film resistance elements,respectively wherein the plurality of metal thin film resistanceelements splits a voltage output and the voltage output is adjusted bycutting one or more of the fuse elements.
 7. The semiconductor device ofclaim 3, further comprising: a splitting resistance circuit including aplurality of fuse elements connected in parallel to the plurality ofmetal thin film resistance elements, respectively, wherein the pluralityof metal thin film resistance elements splits a voltage output and thevoltage output is adjusted by cutting one or more of the fuse elements.8. The semiconductor device of claim 4, further comprising: a splittingresistance circuit including a plurality of fuse elements connected inparallel to the plurality of metal thin film resistance elements,respectively, wherein the plurality of metal thin film resistanceelements splits a voltage output and the voltage output is adjusted bycutting one or more of the fuse elements.
 9. The semiconductor device asclaimed in claim 5, further comprising: a first splitting resistancecircuit which splits an input voltage and supplies a split voltage; astandard voltage generation circuit which supplies a standard voltage;and a voltage detection circuit having a comparison circuit whichcompares the split voltage from the first splitting resistance circuitand the standard voltage from the standard voltage generation circuit.10. The semiconductor device as claimed in claim 5, further comprising:an output drive which controls output of an input voltage; a firstsplitting resistance circuit which splits an output voltage and suppliesa split voltage; a standard voltage generation circuit which supplies astandard voltage; and a constant voltage generation circuit having acomparison circuit which compares the split voltage from the firstsplitting resistance circuit and the standard voltage from the standardvoltage generation circuit.